Center-pull packages are packages which permit yarn, fibers or any material which has been coiled or wound for delivery, to be removed from an interior region of the package rather from the outside or exterior of the package. A bobbin or spool is provided on which the material has been wound.
Center-pull packages of the foregoing type have been used for some time in the textile and fiberglass industries as they provide a substantially free and unrestricted delivery for unwinding the fiber over an extremely wide speed range from a stationary or non-rotating package. By providing the package as a non-rotating fiber dispensing package, it is not necessary to provide the machinery on which a bobbin or spool would otherwise be placed so as to rotate the bobbin or spool and permit the package material to be unwound. Center-pull packages are typically produced on special winding equipment having a collapsible mandrel which can contract after the package has been wound and permit the finished package to be slipped off the mandrel, thereby exposing the inner surface of the cylinder package for withdrawal of the fiber. In order to support the center-pull packages of the prior art, special packing techniques have sometimes been required to support and protect these packages while they are in transit from manufacturer to user.
An example of a center-pull package is disclosed by U.S. Pat. No. 2,596,970 which discloses a packaging technique for a coil of wire or cable. Therein, the wire is wound upon a mandrel which has a tubular leather sleeve placed around the mandrel prior to winding the wire on the mandrel. The wire or cable is wound on the mandrel until the coil of wire or cable reaches any predetermined outside diameter. After the predetermined outside diameter is obtained, the coil of wire or cable is then removed from the mandrel and a central pay out opening permits the wire to be withdrawn therethrough. U.S. Pat. No. 533,688 is also representative of the prior art in which a roll of material is wound onto a driven spindle. After the roll of material has reached a predetermined size, it is then removed from the driven spindle.
U.S. Pat. Nos. 3,732,974 and 3,785,483 are also examples of packages for the handling and transportation of fibers. Both patents disclose the use of packages in which the fiber material is discharged from the external winding portion.